1. Field of the Invention
The present invention relates to a valve opening/closing drive device wherein a valve element is operated by driving of a motor to open or close a flow passage.
2. Description of Related Art
A valve opening/closing drive device has been conventionally known as a device for opening or closing a flow passage or the like for a refrigerant in a refrigerator or an air conditioner to perform a temperature control in a chamber communicating with the flow passage. The valve opening/closing drive device has a valve element used as an opening or closing valve which advances or retreats in an axial direction by a rotary force of a motor. A general constitution is described as follows.
As shown in FIG. 18, a main body case 502 of a valve opening/closing drive device 501 includes two case members 502a, 502b brought into contact and joined with each other. A plurality of apertures (not shown in the figure) are formed in the case member 502a which is made of brass, and the respective apertures are joined with an inflow pipe 505 for flowing a fluid to the interior of the main body case 502 and with a outflow pipe 506 for flowing the fluid to the outside of the main body case 502. When assembling, the inflow pipe 505 and the outflow pipe 506 are temporarily held to the through-holes of the case member 502a and then completely fixed by brazing or the like.
A stator case 508 storing a stator portion of a motor 507 inside thereof is fixed to the outer peripheral face of the main body case 502. FIG. 18 shows a view before the stator case 508 is fitted to the main body case 502 in the direction shown by an arrow Xxe2x80x2.
Accordingly, the stator portion held inside the stator case 508 is fitted to the main body case 502 in a positioned state. As a result, the stator portion is opposed to a rotor, which is disposed rotatably within the main body case 502, interposing the main body case 502. A valve element for advancing or retreating in an axial direction by rotation of the rotor is provided in the main body case 502 and one of the apertures are opened or closed in accordance with advancing or retreating operation of the valve element.
In the conventional valve opening/closing drive device, the inflow pipe 505 and the outflow pipe 506 are completely fixed to the case member 502a by brazing or the like after the inflow pipe 505 and the outflow pipe 506 are temporarily held in the through-hole of the case member 502a. When the case member 502a joined with the inflow pipe 505 and the outflow pipe 506 is made of brass, the case member 502 can be made thick. Accordingly, the inflow pipe 505 and the outflow pipe 506 can be inserted into the through-hole of the thick case member 502a, the temporary holding of the inflow pipe 505 and the outflow pipe 506 can be performed surely before complete fixing.
However, the brass case member 502a causes an increase in manufacturing cost. For this reason, from the standpoint of the manufacturing cost, it is preferable to use a press mould product whose manufacturing cost is inexpensive for the case member joining the inflow pipe 505 and the outflow pipe 506. On the contrary, when the case member 502a is formed by a press mold product, the case member 502a cannot be made so thick due to the nature of mold. Therefore the through-hole formed in the case member 502a is not so deep. Therefore, it is difficult to hold the inflow pipe 505 and the outflow pipe 506 temporarily when they are attached to the main body case 502.
It is therefore an aspect of the present invention to provide a valve opening/closing drive device that is able to temporarily holds a pipe securely with respect to a main body case even when the main body case is manufactured with an inexpensive press molded member.
In order to achieve the above aspect, according to the present invention, there is provided a valve opening/closing drive device including a main body case which is connected respectively with an inflow pipe for fluid intake and an outflow pipe for fluid output and guides the fluid from the inflow pipe to the outflow pipe through the main body""s inside passage. The device also includes a valve element which opens or closes an opening part provided in the main body case connected to the an inflow pipe or the outflow pipe and a driver provided with a motor having a stator part placed on the outside of the main body case and a rotor part for opening or closing the valve element. A holder member is included that is supported by the main body case and provided with a temporary holding part for temporarily holding the inflow pipe or the outflow pipe when the pipes are joined with the main body case.
In this configuration, since the holder member supported by the main body case is provided with the temporary holding part for temporarily holding the inflow pipe or the outflow pipe when the pipe is joined with the main body case, the joint operation can be performed while satisfactorily keeping the position or orientation (joint angle, position or the like) of the inflow pipe or the outflow pipe.
Preferably, the holder member is provided with a fixing part for positioning and fixing the stator part. In this case, since the stator part and the main body case are positioned through the holder member, the positional accuracy can be maintained even if the main body case expands by the fluid pressure. In the case that the valve element is constituted of a ball valve, a disc plate or the like which is easy to encounter a positional deviation in a rotating direction, according to the embodiment, the main body case and the stator part can be uniquely positioned by the holder member in an axial and rotational direction. Therefore, the mechanical home position and the electrical home position of the stator part can be positioned securely and a positional deviation in the rotational direction can be prevented.
Preferably, a ring-shaped boss member is fixed in the aperture part to perform temporary holding of the inflow pipe or the outflow pipe together with the temporary holding part of the holder member when they are joined with the main body case. In this configuration, the aperture part of the main body case can be constituted in a simple hole and thus its machining can be performed easily. Besides, since the boss member fitted in the aperture part can be utilized as the temporary holding part, the inflow pipe or the outflow pipe can be also easily attached to the main body case.
Preferably, the main body case is constituted of a case body having an opening part, and a base plate having a fixing part for respectively fixing the inflow pipe and the outflow pipe and closing the opening part of the case body, and the holder member is provided with passing-through holes separated from the fixing parts by a prescribed dimension for abutting the outer peripheral faces of the inflow pipe and the outflow pipe.
By this construction, even when the inflow pipe or the outflow pipe is bent depending on the specification, the bending stress does not concentrate on the fixing part only and is dispersed to the holder member through the passing-through hole abutting with the outer peripheral face of the inflow pipe and the outflow pipe. Therefore, at the bending processing, a crack will not occur in the fixing part of the base plate. In addition, the above described passing-through hole can be made a guide for brazing when the outflow pipe or the inflow pipe are brazed in the opening part.
Preferably, the fixing part of the base plate is constituted of a step-like part inserted by the end part of the inflow pipe or the outflow pipe. The step-like part cooperates with the temporary holding part to perform the temporary holding when the inflow pipe or the outflow pipe is joined with the main body case.
In this construction, when the inflow pipe or the outflow pipe is attached and fixed to the base plate, the temporary holding before brazing, for example, can be performed easily and securely by the above described step-like part. That is, the fixing part of the base plate is formed as a stepped portion. The end part of the inflow pipe or the outflow pipe abuts against the deepest part of the step-like part, and the portion apart from the end part of the pipe abuts with the temporary holding part. Therefore, the temporary holding can be reliably realized at two positions. Further, the step-like part contributes to ensure the surface area for brazing to make the fixed strength increase and prevent the leak of the fluid inside from the fixing part of the inflow pipe or the outflow pipe.